Copolymerization of Ethylene and 1-Hexene Using (n-BuCp)_2ZrCl_2 Catalyst Activated by the Cross-linked MAO Supported Cocatalyst

摘要

Metallocene/methylaluminoxane (MAO)catalytic systems have grown in importance since their discovery in the 1980s.Many studies concerning the effect of metallocene structures both on catalyst copolymerization reactivity and on copolymer properties have been carried out.Copolymers of ethylene with alpha-olefms such as 1-butene,1-hexene and 1-octene are very important commercial products classified as linear low density polyethylene (LLDPE).There have been many efforts towards finding more efficient catalysts to produce copolymers having desired physical properties.Ziegler-Natta catalysts produce copolymers with wide molecular weight distribution (MWD)and short chain branching distribution (SCBD)because of multiple active sites.In contrast,homogeneous metallocenes are single-site catalysts and produce very uniform copolymers with a narrow MWD and SCBD.